Lubricating oil compositions



United LUBRICATING on. COMPOSITIONS Harlan M. Smith, Roselle, William Hoernner, Linden, and James R. Davidson, Iselin, N. 3., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application November 1, 1954 Serial No. 466,196

4 Claims. (Cl. 252-325) This invention relates to lubricants and more particularly relates to lubricating oil compositions useful as crankcase lubricants for internal combustion engines and to addition agents for such compositions which reduce the wear of engine parts.

The utilization of additives in lubricating oil compositions is well known. Such additives have been used to improve various characteristics of lubricating oil base stocks such as viscosity index, pour point, odor, corrosivity, oiliness, film strength, detergency, etc. The need for improved lubricating oil additives continues to increase as the severity of engine operation becomes greater. It has recently been found that conventional lubricating oil compositions have been deficient in preventing wear of certain engine parts, particularly in high horsepower output V-8 engines. This wear of engine parts has occurred particularly in the valve gear or train of these V-type engines. More specifically, difiiculties have been encountered with the cam lobes, cam followers and rocker arms in these valve trains. Valve train wear is particularly severe with overhead valve V-8 engines. Wear on lobes of camshafts and on faces of cam followers is the most serious type of wear. In an advanced stage it can cause noisy operation, less eflicient engine operation due to the fact that valves are opened less widely, and in an extreme stage the valves do not open widely enough to permit operation at all. There has thus been a critical need for lubricating oil compositions which, in addition to having the conventionally desirable properties of detergency, viscosity index and the like, also will reduce the wear of engine parts.

It has now been found that esters derived from ricinoleic acid are exceedingly effective in reducing such valve train wear. It has also been found that a combination of these esters and zinc dialkyl dithiophosphates is even more effective than the individual materials themselves in reducing valve train wear. More specifically, the improved lubricating oil compositions of this invention comprise a major proportion of a lubricating oil base stock, in the range of about 0.05 to 2.5% by weight,

based on the total composition, of a zinc dialkyl dithiophosphate having in the range of about 3 to 20 carbon atoms in each alkyl group, and in the range of about 0.1 to 1.5% by weight, based on the total composition,

of an ester derived from ricinoleic acid. Preferred lubricating oil compositions of this invention also contain in the range of about 0.5 to 15% by weight, based on the total composition, of a detergent selected from the group consisting of alkaline earth metal alkyl phenol sulfides, alkaline earth metal sulfonates and mixtures thereof.

Other preferred compositions also include viscosity index improvers such as olefin polymers and ester polymers.

The zinc dialkyl dithiophosphates of this invention have the following formula i [(ROhP-SJZD,

2,824,836 Patented Feb. 25, 1958 ice isopropyl hexyl dithiophosphate, zinc isopropyl 2-ethyl-,.

hexyl dithiophosphate, zinc amyl methylcyclohexyl dithiophosphate and the like.

The preparation of these zinc compounds is well known in the art and is based on the following reactions:

OR OR 'OR (2) The zinc dialkyl dithiophosphates are preferably prepared by reacting the alcohols, or alcohol mixtures,

with phosphorus pentasulfide preferably in the ratio of about 1 mole of P 8 to about 4 moles of the alcohol. This reaction is preferably carried out with agitation at an elevated temperature in the range of about 165 to 215 F. in the presence or absence of a solvent until the evolution of hydrogen sulfide substantially ceases. The zinc salts are then produced from the free dithiophosphoric acid esters so obtained by introducing approximately the theoretical quantity of zinc or zinc oxide with agitation at about 120 to 210 F. until a solution of the zinc salt is obtained. Alternatively, the alkali.

metal salts of the dithiophosphoric acid esters may be formed initially by neutralization with alkali carbonates or hydroxides and subsequently these alkali metal salts may be converted to the corresponding zinc dithiophosphates by double decomposition with an aqueous solution of a zinc salt.

The alcohols utilized in the preparation of the zinc dialkyl dithiophosphates of this invention are those having about 3 to 20 carbon atoms and are preferably those containing about 3 to 12 carbon atoms per molecule.

As examples of these alcohols may be mentioned propyl,v

isopropyl, butyl, isobutyl, amyl, isoamyl, hexyl, iso-hexyl, n-octyl, iso-octyl, Z-ethylhexyl, n-decyl, isodecyl, dodecyl, tetradecyl, octadecyl, methylisobutyl carbinol, methyl cyclohexyl, and various alcohols produced from polymers and copolymers of propylene and butylenes via the well-known 0x0 reaction. Of the latter may be mentioned specifically the C Oxo alcohol produced from C propylene-butylene dimer, the C alcohol produced from tri-propylene, the C alcohol produced from tetrapropylene and the C alcohol produced from pentapropylene.

The esters useful in this invention are those derived from ricinoleic acid. Acids derived from castor oil by saponification and subsequent acidification may also be employed to form the esters of this invention. These acids derived from castor oil contain about 85% by weight of ricinoleic acid and small amounts of other acids such as oleic, linoleic and stearic acid.

Condensation polymers of ricinoleic acid may also be employed in forming the esters of this invention. These condensation polymers are formed by reacting the car molecules, preferably about 2 to 4 molecules, of ricinoleic acid may be combined to form a condensation polymer vention. V 1

. 3 containing one free carboxylic acid group and one free hydroxyl group. ,Thus, for example, di-, tri-, tetra-, penta-, and hexa-ricinoleic acid may be formed. The condensationireactionmay be carried out simply by heating ricinoleicaacid at a temperature above about 210 F.

- as is well known in the art. This reaction generally forms amixture of polyricinoleic'acidsl Such mixtures may be employed in this invention. These condensation polymers mayjthen be esterified to form esters useful in this in- The ricinoleicracid esters of this invention are prefer- 7 ably those of glycols or polyglycols which contain inthe ran-geofabout 2 to 100 carbon atoms per moleculeand. more preferably are those of gly'cols or polyglycols which contain in the range of-about 2 to 49 carbon atoms per molecule. .The preferred glycols contain at least one ether oxygen inthe molecule. Thus, polyalkylene glycols, such' as polyethylene glycol, polypropylene glycol, polybutylene glycol, and the like, are useful in this invention. The

V glycols useful in thisinvention have the general formula 7 where y is an integer of l to '50, preferably 1 to 20, and n is an integer of 2' to 4. Specific examples of the glycols useful in this invention include the following:

Ethylene glycol Diethylene glycol Tetraethylene glycol Nonaethylene glycolf 'Tetracosaethylene glycol Propylene glycol Tetrapropylene glycol Tetradecapr'opy'lene glycol Butylene glycol Tributylene glycol Dodecabutylen e glycol Ricinoleic acid esters of alcohols may also be used in certain instances although these esters are less effective than those formed from glycols orpolyglycols. Such alcohols include-methyl, propyl, butyl, amyl, octyl, decyl, dodecyl,

' C to C Oxo alcohols obtained by the oxonation of C to C olefins or olefin polymers, alcohols derived from coconut oils', etc. s p

The esters of this invention are prepared by esterifying ricinole'i'c acid, castor oil acidslpredominantly ricinoleic acid) or polyricinoleic acids with the above-mentioned glycols, polyglycols, alcohols or mixtures thereof by conventional esterification methods, which are well known to the art; A particularly preferred ester useful in this invention is a polyethylene'glycol di-t'riricinoleate, con

taining 'a glycol residue having a molecular weight in'the range of about 200 to 800, preferably about 40.0.. Other ricinoleates include monoricinoleate-polyethylene glycol pentaricinoleate; diricinoleate polyethylene glycol tetraricinoleateand the'like.

The alkaline earth metalgsalts ofalkyl p'heno'l'sulfides 1 which are'ufilized in preferred lubricating oil compositions; may be obtained by the alkylation of phenol followed by treatment with a sulfur halide and neutralization phenol; or it may be alkylated with other olefin polymers p iii withan alkaline earth metal base and have the following 7 general formula:

whereR'is'an'alkyl radicalcontaining about 4' to 24 carbon atoms, .and preferably about- 6 to 12-carbonatoms, M

' is an alkaline earth metal and x is an integer from 1 to 4,

preferably '1 to 2. The preparation of these alkaline metal salts ofphenolsulfides .is well known tothe art.

sulfuric acid, phosphoric .acid, or certain activated clays}; As olefinic reactants, refinery gases containing propylene,

butylenes, amylenes, etc., are economically useful, al-

though individual olefins or olefin-containing mixtures derived fromother sources may be used. Preferred in-;

'dividual'olefins are the butenes, amylenes and olefin poly mers, such as tripropylene, diisobutylene or triisobutylene or normal olefin polymers or copolymers of normal and secondary or tertiary olefins orcopolymers of olefins and 'diolefins. The reaction temperature is usually controlled to avoid side reactions. In employing sulfuric acid a liquid phase reaction at relatively'low temperature is pre ferred, while with phosphoricacid the reaction rnay be carried out in the vapor phase.

,One class of alkyl phenols which are particularly preferred are those which have been preparedjlby alkylation of phenol with an olefin polymer such as diisobntylene or a refinery butene polymer oil. Alkylation of phenol with about an equal molar proportion of diisobutylene 1 gives p-terL-octyl phenol, also known as diisobutyl phenol or tetramethyl butyl phenol. This phenolic material is especiallyv desirable because of the ease of itspreparation and because products made from it are highly satisfactory-for the present invention. In manyinstances, howe ever, a higher degree of alkylation may be advantageous, and for this reason the phenol may be alkylated with as j much astwo molecular equivalents of diisobutylene to;

give, under proper conditions, essentially-di-tert.-octyl suchas triisobutylene or other isobutylene polymers.

Another class of alkyl "phenols which are esp cially preferred are those which are prepared by alkylation of phenol with tripropylene utilizing BF as'a catalyst.

Alkylation of phenol with an equal molar proportion of tripropylene gives tripropyl phenol.

of tripropylene to give, under proper 'iconditions, essen tiallydi-tripropyl phenol.

Suitable products may also be prepared by alkylating phenol' with-certain of the polymeric materials obtained as lay-products in-the manufacture of butyl alcohol from petroleum'refinery butenes. These consist essentially of V polymers of n-butene withsmall percentages of isobutene and 'othenolefins and give. alkylated phenolsghaving.

branched chain alkyl groups of 16 20 or 26 -24' carbon atoms dependingon the polymeric material used in the alkylation It should he understood'that inmanycases the alkylation products maybe mixtures of various 1Com pounds rather than entirely one specific alkyl phenol and that it is intended to use suchmixtures in practicing this V invention. V t

For conversion .of the alkyl phenol to an alkylphenol sulfide, the .alkyl phenol is reacted'wit'h sulfur dichloride to' producev essentially a illhcnol :monosulfide having a thioether linkage, while sulfurmonochloridemay be used i to produce essentially the phenol ,disulfide. 'About one half to one mole of sulfur halide is used 'is'ith .each mole of alkyl phenol, and the reaction is preferably carried out in a solvent such as dichlorethane, chloroform, petroleum naptha, benzol, xylol, toluol, and the like. phenol sulfiides prepared as abovenray be illustrated by the following general classes of, compounds.

This phenolic 'material is also excellent'forthe purposes of the present invention. In certain instances a higher degree of alkyla tion may be advantageous and in'this'case the phenolmay' be .alkylated with as much as .two molecular equivalents These alkyl Monosulfides: V

Y on on Disulfides:

OH OH R s R s OH on In the above structural formulas, the alkyl groups contain 4 to 24 carbon atoms and preferably contain 6 to 12 carbon atoms. It will be understood that in the formation of the mono-sulfides and disulfides, small amounts of polysulfides will also be formed. This is even more usually the case where more than the theoretical quantity of sulfur halide is employed in preparing the alkyl phenol sulfide.

For converting the alkyl phenol sulfides to metal salts it is usually sufiicient merely to add an alkaline earth metal or an alkaline earth metal oxide, hydroxide, sulfide, alkoxide, hydride or carbide to a mineral oil solution or other solution of the phenol sulfide at an elevated temperature. Thus, barium salts of alkylated phenol sulfides are prepared by reacting the sulfide with barium hydroxide, preferably in the form of the hydrate, Ba(OH) .8H O. In some instances it may be preferable to prepare these salts from the alkali metal salt by double decomposition. The calcium salts are conveniently prepared by reacting alkyl phenol sulfides with calcium methylate or other calcium alcoholate.

In many cases the metal alkyl phenol sulfide prepared by neutralizing with a metal hydroxide may occur as a hydrated salt. Use of hydrated salts prepared in this manner or by anyother method is also contemplated in the present inventon. The alkaline earth metal salts include those of calcium, barium, strontium and magnesium, calcium and barium being the preferred metals. Mixtures of salts of different alkaline earth metals may be employed if desired.

The alkaline earth metal sulfonates useful in this invention include those of calcium, barium, strontium and magnesium. The preferred sulfonates are those of calcium and barium. Petroleum, sulfonates and particularly the alkaline earth metal soaps of oil soluble or so-called mahogany acids which are usually produced during treatment of lubricating oil distillates with concentrated to fuming sulfuric acid are particularly useful in this invention. Such sulfonates are well known to the art and are described, for example, in U. S. Patent No. 2,467,176, etc. The more desirable high molecular weight (350 to 550) acids, particularly those produced when treating white oil with fuming acid, are normally recovered as sodium soaps by neutralizing the acid oil with sodium hydroxide or carbonate, extracting the soaps with aqueous alcohol, distilling off the alcohol and purifying the soap by well-known means from contaminating salts (such as sodium carbonate, sulfate, etc.).

The alkaline earth metal sulfonates may be prepared by direct neutralization of the acid treated oils with an gxide or hydroxide of the desired metal. However, it is index improver.

often moreconvenient to prepare them from the sodium; salts by double decomposition. Thus the alkaline earth metal sulfonates may be made by precipitation from alcoholic solution with an alkaline earth metal salt. Or an oil solution of sodium sulfonates may be emulsified with an aqueous solution of the alkaline earth metal salt. For example, the calcium metal sulfonates may be prepared by precipitation from alcohol solution with calcium chloride, the inorganic salts then being removed by washing with water. It will be understood that other sulfonates such as those of alkyl aromatic benzenes, e. g. didodecylbenzene, alkyl naphthalene, etc., may be utilized in this invention. Also, sulfonates prepared by photochemical methods may be employed. Likewise, mixtures of sulfonates of several alkaline earth metals may be used in this invention. The sulfonates are preferably employed in this invention with the alkyl phenol sulfide salts in a ratio of alkyl phenol sulfide salt/sulfonate of about 1:1 to 5:1 on a weight basis.

Preferred compositions also may include a viscosity The preferred viscosity index additive is a high molecular weight polymerized olefin such as polymerized C to C olefins; for example, polymerized butenes, especially polymerized isobutylene having a molecular weight in the range of about 5,G00 to 50,000; preferably, about 10,000 to 20,000 are quite useful. These polymerized olefins are readily preparedby procedures well known to the art. Such additives are also useful as thickening agents for increasing the viscosity of relatively light oil base stocks. Other viscosity index improvers include the polymethacrylate esters, fumarate-vinyl acetate copolymers, polyalkyl styrenes, and the like.

The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from parafiinic, naphthenic, asphaltic or mixed base crudes, or if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The oils may be refined by conventional methods using acid, alkali, and/ or clay or other agents such as aluminum chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichloro ethyl ether, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or White oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. coal tar fractions and coal tar or shale oil distillates may also be used. Also, for special applications, animal, vegetable or fish oils, or their hydrogenated or voltolized products, may be employed, either alone or in admixture with mineral oils.

Synthetic lubricating oils having a viscosity of at least 30 SSU at F. may also be employed, such as esters of monobasic acids (e. g. ester of C Oxo alcohol with C Oxo acid, ester of C Oxo alcohol with octanoic acid, etc.), esters of dibasic acids (e. g. di-Z-ethyl hexyl sebacate, di-nonyl adipate, etc.), esters of glycols (e. g. C acid diester of tetraethylene glycol, etc.), complex esters (e. g. the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of Z-ethyl-hexanoic acid, complex ester formed by reacting one mole of tetraethylene glycol with two moles of sebacic acid and two moles of 2-ethyl hexanol, complex ester formed by reacting together one mole of azelaic acid, one mole of tetraethylene glycol, one mole of C Oxo alcohol, and one mole of C 'Oxo acid), esters of phosphoric acid (e. g. the ester formed by contacting three moles of the mono methyl ether of ethylene glycol with one mole of phosphorus oxychloride, etc.), halocarbon oils (e. g. the polymer of ch1orotrifiuoroethylene containing twelve recurring units of chlorotrifiuoroethylene), alkyl silicates (e. g. 'methyl polysil-,

In certain instances cracking oiliness agents, resins, rubber,

V oxanes, ethyl polysiloxanes, methyl-phenyl polysiloxanes,

ethyl-phenyl polysiloxanes, etc), sulfiteesters (e. g.- est er formed by reacting one mole of sulfur oxychloride with 7 two moles ofthe methyl ether of ethylene glycol, .etc.), carbonates (e. g. the carbonate formed by reacting .C Oxo' alcohol with ethyl carbonate to form a 'half ester and reacting this half'ester with tetraethylene glycol), mercaptals (.e'. g. the mercaptal formed by reacting '2- ethyl hexyl mercaptan with formaldehyde), formals (e. g; the formal formed by reacting C .Oxo alcohol with formaldehyde), polyglycol type synthetic oils. (e. g.

the compound formed by condensing butyl alcohol with fourteenunits of propylene oxide, etc.), or mixtures of any of the above in any proportions. Mixtures of these synthetic oils and mineral oils and/ or other oils described heretofore may also be'employed if desired.

For the best results the base stock chosen shouldnormally be that oil'which without the new additives present gives the optimum performance in the service contemplated. However, since one advantageof the additives is that their use also makes feasible the employment of less satisfactory mineral oils or'other ,oils, no strict rule can be. laid down for the choice of the base stock. 7 Certain essentials must of course be observed. The oil must possess the viscosity and volatility characteristics known a concentration in the range of about 0.5 to 15% by Weight 7 to be requiredfor. the service contemplated. The oil f must be a satisfactory solvent for the additives, although in some cases auxiliary solvent agents may be used. The

; lubricating oils, however'they'may have been produced,

may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 34-to 150 secmethacrylate esters, may be used in amounts in the range onds Saybolt viscosity at 210 F. i For the lubrication of certain low and medium speed diesel engines the general practice has been often been to use. a lubricating oil base having a Saybolt viscosity at 210 F. of to 90 seconds and a viscosity index of 0 to 50. However, in certain types of diesel service, particularly with high speed diesel engines, and in aviation engine andother gasoline engine service, oils of higher viscosity. index are often preferred, for example, up to 75 to 100, or even higher viscosity index; i

Particularly preferred lubricating oils for. automotive engines are those described in copending application Serial Number 375,158 by Leonard E. Moody and Alexander H. Popkin, filed August 19, 1953, now abandoned, which have a low resinification index, that is, lubricating oils which have relative freedom from formingit'ena'ciously adhering resin-like deposits when subjected to combus- .tionin a container under'a hot, smokeless flame, such as 7 stock prepared from naphthenic or aromatic crudes and r a hydrogen flame. In particular, refined m-ineraloil distillates obtained from parafiinic or naphthenic-base crude oils and boiling essentially within the range of about 275 to 600 F., preferably within the range of about 300 to 575 F., at 10 min. Hg absolute, are preferred base stocks.

In addition to the materials to be added to the lubrficating oil base stocks according to the present invention,

which, as described heretofore, include mineral. oils and synthetic: oils or mixtures thereof. Quite generally, the lubricatinjg'oil base stock Will represent in'the range of about to 99.9% by Weight of the total composition.

The zinc dialkyl dithiophosphates are utilizedin the lubricating oil compositions in a proportion in the range of about 0.05 to 2.5% by weightbased on the total compo sition, preferably in the range of about 0.1 to 1.5 .by 1

The esters of 'ricinoleic acid are utilized'in: the

weight. lubricating oil compositions at a concentration in the range of about 0.1 to 1.5% by Weight based on the total composition, preferably at a concentration in the range of about 0.2 to. 0.7% by weight. The combination of the zinc dialkyl dithiophosphate and the ester of ricinoleic acid is preferably such that the-weight ratio of dithid-g phosphate to ricinoleate is in the range of about 1:2 to 4:1, and more preferably 'in the range of about 1:11 to 3:1. The detergent inhibitor, which maybe an alkaline M earth metal alkyl phenol sulfide, an alkaline earth metal sulfonate or a mixture thereof, when included in the com-'v positions of this invention, is utilized in'general at at based on the total composition and preferably at a concentration in the range of about 1.0 to 5.0% by weight. When viscosity; index improvers'of the polyolefin type,

such as polymerized polyisobutylene, are included in the compositions of this invention, it is generally desired to employ them at a concentration in the range of about 0.5

to 30.0% by Weight, preferably about 1 to 10% by weight based. on the total composition. As a general rule, viscosity index improvers. of the polyester type, such as pol yofabout 0.5 to 5.0% by weight. Lubricating oil compositions containing a mixture of polyolefins and polyesters may be formulated if desired. Thus, from about 3 to 7 10% of polybutene and about 1 to 3% of a polyester may be used. 7

The invention will be more fully understood by reference to the following examples.

the scope of the present invention'in any way.

Various compositions formulated in accordance with this invention were evaluated in a Cadillac V-8 valve train Wear test. This test is carried out in the following manner. A1952 or 1953 Cadillac engine is assembled and operated as follows:

First phase.-The engine is operated with a water jacket outlet temperature of 165 F. and an 'oil sump temperature in the range of 1 to 200 F. under zero load conditions for two hours at the following speeds:

' Hours I Speed Second phase.The engine is then operated for a number of 4-hour cycles according to the following schedule:.

Hours Operating Conditions 2.; 11112312. P. M., Zero Load, F. Water Outlet Tempera e. r

2 Cold Water Running Through the Engine Block. Engine Shutdown. V v i 7 V r The first phase is termed the two-hour Cadillac valve-v train wear'test and the first phase plus the second,

phase when carried outfor a-total of 100 hours'is termed the 100-hour Cadillac valve trainwear test.

'In each test a new filter element 1s employed and the initial oil charge is6 quarts. Standard. valve springs.

. lbs.) and a new camshaft and new tappets are used .in each test. Before and after each test, all of the 16 tappets and cams are measured and'tbe average diflt isr pointed out, how-' ever, that the examples are given for the purpose of illustration only and are not to be construedas limiting wear tests: Base stock 1: Volume percent V. I. improver A 7.4 V. I. improver B 2 2.6 Lubricating oil 90.0

An oil solution containing as the active ingredient about 20% by weight of a puly1sobutylene having a Staudinger molecular weight or about 18,000.

An oil solution containing as the active ingredient about 45% by weight of a polymerized reaction product of C8 to C12 alcohol esters of metnacrylic acid, the polymerized reaction product having, a Sraudinger molecular weight of about 13 ,000.

A solvent extracted and dewaxed mineral oil distillate havi g a. viscosity or 75.7 SSU at 100 F. and a viscosity of 37.2 SSU at 210 F.

Base stock II: Volume percent V. I. improver B 1 3.2 Lubricating oil 96.8

1 Same as used in base stock I.

A mineral lubricating oil having an API gravity of 31.7, a pour point of 1:1, an StlU viscosity at 210 F. of about 38.8 and a viscosity index of about 102.

Base stock Ill: Volume percent V. I. improver B 1 5.2 Lubricating oil 94.8

1 Same as used in base stock I.

*A 1PIllillllbltlzltlll oil of 5W 20 grade. Base stock III has an 5.51. viscosity al 210 1 of 5.3.3 and at 100 F. of 212.5.

The following detergents were employed in the compositions evaluated in the valve train wear tests:

Detergent A.This additive consisted of (1) 62.5% by weight of an oil solution containing as the active ingrediem 40% by weight of an 80%-20% mixture of calcium and barium tert.-octyl phenol sulfides and (2) 37.5% by weight of an oil solution containing as the active ingredient 30% by weight of calcium petroleum sulfonates.

Detergent B.--This additive consisted of (l) 62.5% by weight of an oil solution containing as the active ingredient 40% by weight of barium tert.-octyl phenol sulfide and (2) 37.5% by 'weight of an oil solution containing as the active ingredient 30% by weight of calciumpetroleum sulfonates.

Detergent C.-This additive consisted of an oil solution containing, as the active ingredient, about 30% by weight of predominantly calcium didodecylbenzene sulfonate.

' Detergent D.This additive consisted of an oil solu-:

tion containing as the active ingredient about 40%Iby weight of an 80%20% mixture of calcium and barium tert.-octyl phenol sulfides.

' The following additives of this invention were employed in the valve train wear tests:

Ricinoleale-Polyethylene glycol di-triricinoleate (containing an average of about 9 ethylene oxide units in the glycol portion).

Dizlziophosphate conc.An oil solution containing as the active ingredient about 55% by weight of zinc di isohexyl dithiophosphate.

Dizhiophosphate.Zinc di isohexyl dithiophosphate. Another additive which was employed in several of the compositions was a P 5 treated terpene which will be designated as additive X.

10 EXAMPLE I The following two lubricating oil compositions were evaluated in the 2-hour Cadillac valve train wear test:

Composition A Formulation: Volume percent Detergent A 5.0 Base stock I 95.0

100.0 Composition B Formulation: Weight percent Composition A 99.75 Ricinoleate 0.25

The following results were obtained in the wear tests:

Table I 2-Hour Wear Test (Wear in InchesXl0 Composition Average Range of Wear Wear A 6.8 3 to 9 B 4.1 1 to 7 It will be noted that the addition of polyethylene glycolditriricinoleate to the lubricating oil composition reduced wear in the valve train of the Cadillac engines.

EXAMPLE II The following lubricating oil compositions were also evaluated in the 2-hour Cadillac V-8 valve train wear test:

Composition C Formulation: Volume percent Detergent R 8.0 Base stock I 92.0

100.0 Composition D Formulation: Weight percent Composition C 99.50 Ricinoleate 0.50

Composition E Formulation: Weight percent. Composition C 99.50 Dithiophosphate conc 0.50

100.00 Composition F Formulation: Weight percent Composition C 99.50 Ricinoleate 0.25 Dithiophosphate conc 0.25

100.00 Composition G Formulation: Weight percent Composition C 99.50 Ricinoleate 0.25 Dithiophosphate 0.25

The following results were obtained with these five lubricating oil compositions in the 2-hour Cadillac V-8 valve train wear test:

Base stock III It be noted that the combination ofo'th'e ricinolea'te' and zinddi isoheXyl dithiophosphate (compositions F and a (3) demonstrated synergism. Thus the combination was better than either the ricinoleate (composition 'D) or the dithiophosphate (composition E) when these additives were employed separately. 7 a V l EXAMPLV'E III The following two lubricating oil compositions were 7 evaluated in the 100-hour Cadillac V -8 valve train wear test: 7 4 V Composition H Formulation:

Volume percent name Detergent B g 8.0 Base stock'II 7 92.0

7 1 Composition I a Detergent B 8&0 Ricinoleate V0.13 Dithiophosphate conc; 0.26 7 Base stock Tl a 91.61

' mono 'These two lubricating oil compositions gave the follow -t ing results in a IOO-honr Cadillac V8 valve' train wear test: 7

Table III 7 V IOU-Hour Test (Wear in InchesX10 Composition r Average Range or Wear Wear 7 n V 15.4 '7to33 I 12 7 to 19 n will be noted again that the addition of a combination of polyethylene glycol-di-triricinoleate and a 'zinc dialkyl dithiophosphate substantially reduced valve train wear I V in Cadillac engines. J

'EXAMPLE'IV also evaluated in the IOU-hour Cadillac V-'8 valve train wear test: r 7 o v Composition JV Formulation: 7

'Additive mixture 1 Detergent O o 7 r V The following two lubricating oil compositions were I o Volume percent Formulation: o o Volumepercent o Additive mixture Ricinoleate t.;. 0.5 3 Base stock IH 91.0

' Cliooo' a Same as usedincomposition I. V

'Table IV 7 e dooaomooe v o 1 t a 1 .7 (Wearin'InchesXlO) to Q P QWV. to

Average Range of 7 Wear, Wear It will be noted again that the combination of polyethyl-i ene glycol-dhtriricinoleate and zinc .dialkyl dithiophos-j phate' substantially'reduced valve train Wear in Cadillac engines. r a EXAMPLE V' I The following twolubricating oil compositions were alsoevaluated'in -the-1-00-h0ur Cadillac V8 valve train wear test: a

Composition L g V Formulation? f 7 o 7 *Volume percent Detergent'C f 3.5.5. Detergent D7; r 2.13

' Dithiophosphate conc 0.89 Additive'X ;Q ;;;f '0.S3 Base stock I 92.9 0

a CompositionM T Detergent C 3.55 V Detergent D Y g V V 1.881 Dithiophosphate conc 0 89 Ricinoleate W 0. 25

Additive X 10.53

Base stock I p 9290.

7 o v '1 1100.00 The following results were obtained in the TOO-hour; Cadillac V8 valve train wear test: 'f

Table V 7 lflo-Hou r lest 7 (Wear in InchesXlO) Composition Average Range of Wear Wear r; v 7 1s 10 to 25 It will be noted again that the combination o f'polyethylene glycol di-triricinoleate and zinc dialkyl 'dithiophosphate was exceedingly effective in reducing valve train Composition wear in Cadillac engines;

What is claimed is:

to 1.5 wt) percent of a zinc dialkyl dithiophosphate having in the range of Ste 16 carbon atoms per molecule,

and in the range of 0.2 to 70.7 wt. percent of a polyr icinoleic acid ester of a polyethylenetglycol, said glycol: having a molecular weight in the range of'200 to 800- and'said ester being formed froina polyricinoleic acids containing in the range of 2 to 4 molecules of self-esterified ricinoleic acid.

2. The composition of claim 1 comprising, in addition thereto, in the range of 0.5 to 15 wt. percent of a detergent selected from the group consisting of alkaline earth metal alkyl phenol sulfides and alkaline earth metal sulfonates.

3. A lubricating composition comprising a major proportion of a mineral lubricating oil, in the range of 0.1 to 1.5 wt. percent of zinc diisohexyl dithiophosphate, and in the range of 0.2 to 0.7 wt. percent of polyethylene di-triricinoleate containing an average of about 9 ethylene oxide units in the glycol portion.

4. A lubricating composition comprising a major pro- 14 portion of a mineral lubricating oil, about 0.89 wt. per cent of a 55 wt. percent concentration in oil of zinc diisohexyl dithiophosphate, and 0.25 wt. percent of polyethylene glycol di-triricinoleate containing an average of about 9 ethylene oxide units in the glycol portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,210,140 Colbeth Aug. 6, 1940 2,364,283 Freuler Dec. 5, 1944 2,457,139 Fife et al Dec. 28, 1948 2,506,310 Mikeska May 2, 1950 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,824,836 Harlan M. Smith et al. February 25, 1958 It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 13, line 11, after "polyethylene" insert glycol Signed and sealed this 17th day of June 1958.

(SEAL) Attest: KARL H9 AXLINE ROBERT C. WATSON Attesting Officer Comnissioner of Patents 

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL, IN THE RANGE OF 0.1 TO 1.5 WT. PERCENT OF A ZINC DIALKYL DITHIOPHOSPATE HAVING IN THE RANGE OF 8 TO 16 CARBON ATOMS PER MOLECULE, AND IN THE RAANGE OF 0.2 TO 0.7 WT. PERCENT OF POLYRICINOLEIC ACID ESTER OF A POLYETHYLENE GLYCOL, SAID GLYCOL HAVING A MOLECULAR WEIGHT IN THE RANGE OF 200 TO 800 AND SAID ESTER BEING FORMED FROM A POLYRICINOLEIC ACID CONTAINING IN THE RANGE OF 2 TO 4 MOLECULES OF SELF-ESTERIFIED RICINOLEIC ACID. 